Additive Manufactured Ducting with Shielding Air Injector Assemblies
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Solution Overview
Problem
Existing distributed combustion systems face challenges in reducing NOx emissions due to high flame temperatures, which can be attributed to insufficient mixing of reactants with cross-flow combustion products before ignition, and inefficiencies in utilizing cooling air, leading to increased manufacturing complexities and costs.
Innovation Solution
The implementation of injector assemblies that generate a shielding air flow to delay ignition and enhance mixing, combined with the reuse of cooling air to create a shielding effect, and the use of 3D Printing/Additive Manufacturing technologies for cost-effective and complex ducting arrangement fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If distributed combustion system is implemented to reduce NOx emissions, then NOx emissions are reduced, but flame temperature becomes too high causing insufficient mixing
Solution Approach 1:
The patent applies preliminary action by introducing cooling air to the injector assembly before ignition occurs. The cooling air is delivered through conduits that position it to interact with the reactant flow prior to combustion, pre-cooling the mixture and preparing conditions for lower flame temperature. This pre-action approach allows the system to achieve both NOx reduction and controlled flame temperature.
Solution Approach 2:
The cooling air acts as an intermediary substance between the hot combustion process and the reactant flow. By introducing this intermediate cooling air through the injector assembly conduits, the system mediates the temperature interaction, allowing heat transfer that reduces flame temperature while maintaining the distributed combustion structure for NOx reduction.
2Temperature
If cooling air is used for combustion chamber cooling, then chamber temperature is controlled, but cooling air utilization efficiency decreases
Solution Approach 1:
The cooling air serves multiple functions simultaneously: it cools the combustion chamber through traditional pathways and also fuels the distributed combustion process by being introduced to injector assemblies downstream. This multi-functionality increases utilization efficiency, as the same cooling air contributes to both thermal management and combustion reactions, reducing waste.
Solution Approach 2:
The system recovers cooling air that would otherwise be wasted by redirecting it through conduits to injector assemblies where it participates in distributed combustion. This recovery approach transforms previously discarded cooling air into a useful resource for maintaining lower flame temperatures and supporting the combustion process.
3Ease of manufacture
If traditional manufacturing methods are used for ducting arrangement, then manufacturing process is simple, but manufacturing complexity and cost increase for complex geometries
Solution Approach 1:
The patent merges multiple previously separate components into a single integrated ducting arrangement. The ducting structure combines cooling air conduits, injector assembly housings, and flow path components into one monolithic structure manufactured via additive manufacturing. This consolidation simplifies the manufacturing process by reducing assembly steps while enabling complex internal geometries that would be difficult to achieve with traditional manufacturing methods.
Solution Approach 2:
The adoption of additive manufacturing represents a fundamental parameter change in the manufacturing process. This technology enables the production of complex three-dimensional geometries with internal conduits and varying cross-sections that are impossible or economically unviable with traditional subtractive or formative manufacturing methods. The parameter change in manufacturing technology allows simultaneous achievement of design complexity and manufacturing simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces NOx emissions by lowering flame temperature, increases the liftoff distance of the flame, and enhances combustion efficiency while maintaining stable operation at high turbine inlet temperatures, achieving approximately 65% combined cycle efficiency and meeting regulatory NOx emission limits without increased cooling air consumption.
Implementation Method 1
injector assemblies that generate a shielding air flow to delay ignition and enhance mixing
Implementation Method 2
the reuse of cooling air to create a shielding effect
Implementation Method 3
the use of 3D Printing/Additive Manufacturing technologies for cost-effective and complex ducting arrangement fabrication
Data Source
AI summary
Method and computer-readable model for additively manufacturing a ducting arrangement (20) in a combustion stage are provided. The ducting arrangement may include a combustor wall (40) in a combustion stage fluidly coupled to receive a cross-flow of combustion products (21). An injector assembly (12) may be in fluid communication with cooling fluid conduits (46) in the combustor wall to receive cooling fluid that passes through the cooling fluid conduits. The injector assembly may include means for injecting (24, 25, 26) a flow of the cooling fluid (22) arranged to condition interaction of a flow of reactants (19) injected with the cross-flow of combustion products. Respective duct components or the entire ducting arrangement may be formed as a unitized structure, such as a single piece using a rapid manufacturing technology, such as 3D Printing/Additive Manufacturing (AM) technologies.